224 ON GENERATION. 



capable of living, but for the most part speedily die, either by 

 reason of want of room or of air in the shell, or because the 

 one proves a hinderance to the other and blights it; nor can it 

 happen that both should be equally prepared for exclusion that 

 one should not prove an abortion. 



Briefly and summarily the differences among eggs are prin- 

 cipally of three kinds : some are prolific, some unprolific; some 

 will produce males and some females; some are the produce 

 of the two sexes of the same species, others of allied species and 

 will produce hybrids, such as we see between the common hen 

 and the pheasant, the progeny being referrible either to the first 

 or to the last male that had connexion with the hen. Because, 

 according to Aristotle, 1 "the egg, which receives its consti- 

 tution by intercourse, passes from its own into another genus, 

 if the hen be trodden when she carries either an adventitious 

 egg or one that was conceived under the influence of another 

 male, and this renewed intercourse take place before the yellow 

 is changed into the white. So that hypenemic or wind eggs 

 are made fruitful, and fruitful eggs receive the form of the male 

 which has connexion last. But if the change has taken place 

 into the white, it cannot happen either that the wind egg is 

 turned into a fertile one, or that the egg which is contained 

 in the uterus in virtue of a previous intercourse, shall be altered 

 into the genus of the male which has the second communi- 

 cation." For the seminal fluid of the cock, as Scaliger wittily 

 remarks, is like a testament, the last will or disposition in 

 which is that which stands in force. 



To these particulars it might perhaps be added, that some 

 eggs are more strong and lusty than others, more full of life, if 

 the expression may be used ; though as there is a vital principle 

 in the egg, so must there inhere the corresponding virtue that 

 flows from it. For, as in other kinds of animals, some of the 

 females are so replete with desire, so full of Venus, that they 

 conceive from any and every intercourse, even once submitted 

 to, and from a weakly male, and produce several young from the 

 same embrace; others, on the contrary, are so torpid and sluggish, 

 that unless they are assailed by a vigorous male, under the in- 

 fluence of strong desire, and that not once, but repeatedly, and for 



1 Hist. Anim. lib. vi, cap. 21. 



